Messages in this thread Patch in this message | | | Subject | [BUGFIX] kvm, Fix a race condition for usage of is_hwpoison_address | From | Huang Ying <> | Date | Tue, 22 Jun 2010 14:23:11 +0800 |
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is_hwpoison_address accesses the page table, so the caller must hold current->mm->mmap_sem in read mode. So fix its usage in hav_to_pfn of kvm accordingly.
Comments on is_hwpoison_address are added to remind other users.
Reported-by: Avi Kivity <avi@redhat.com> Signed-off-by: Huang Ying <ying.huang@intel.com> --- mm/memory-failure.c | 3 +++ virt/kvm/kvm_main.c | 3 ++- 2 files changed, 5 insertions(+), 1 deletion(-)
--- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1298,6 +1298,9 @@ done: return ret; } +/* + * The caller must hold current->mm->mmap_sem in read mode. + */ int is_hwpoison_address(unsigned long addr) { pgd_t *pgdp; --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -955,12 +955,13 @@ static pfn_t hva_to_pfn(struct kvm *kvm, if (unlikely(npages != 1)) { struct vm_area_struct *vma; + down_read(¤t->mm->mmap_sem); if (is_hwpoison_address(addr)) { + up_read(¤t->mm->mmap_sem); get_page(hwpoison_page); return page_to_pfn(hwpoison_page); } - down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, addr); if (vma == NULL || addr < vma->vm_start ||
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